Soils contaminated with zinc from mining, refining, or fertilizing with zinc-bearing sludge can have several grams of zinc per kilogram of dry soil. Levels of zinc in excess of five hundred ppm in soil interfere with the power of crops to absorb other necessary metals, for example iron and manganese. https://zinc-sulfide97307.bloguerosa.com/27250245/5-tips-about-zinc-sulfide-you-can-use-today